JPH04327573A - Carbazole compound and electrophotographic sensitized material using the same compound - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel carbazole compound, and more particularly to a highly sensitive and highly durable electrophotographic photoreceptor using the carbazole compound of the present invention as a charge transport material.

0002

[Prior Art and Problems] In recent years, the development of copying machines and printers used in electrophotography has been remarkable, and models with various shapes, types, and functions have been developed depending on the application, and correspondingly, the photosensitive A wide variety of bodies are being developed.

Conventionally, inorganic compounds have been mainly used as electrophotographic photoreceptors due to their sensitivity and durability. Examples include zinc oxide, cadmium sulfide, and selenium. However, these often use harmful substances, and their disposal becomes a problem and causes pollution. Furthermore, when selenium, which has good sensitivity, is used, it is necessary to form a thin film on a conductive substrate by a vapor deposition method or the like, resulting in poor productivity and increased costs.

[0004] In recent years, amorphous silicon has attracted attention as a non-polluting inorganic photoreceptor, and research and development thereof has been progressing. However, although these also have excellent sensitivity, since plasma CVD is mainly used to form thin films, their productivity is extremely poor, and both photoreceptor costs and running costs are high.

On the other hand, organic photoreceptors can be incinerated,
It has the advantage of being non-polluting, and in many cases it is possible to form a thin film by coating, making mass production easy. Therefore, it has the advantage of being able to significantly reduce costs and being able to be processed into various shapes depending on the application. However, problems remain in the sensitivity and durability of organic photoreceptors, and there is a strong desire for an organic photoreceptor with high sensitivity and high durability.

Various methods have been proposed to improve the sensitivity of organic photoreceptors, but currently the mainstream is a functionally separated photoreceptor with a two-layer structure in which the functions are separated into a charge generation layer and a charge transport layer. It becomes. For example, charges generated in the charge generation layer due to exposure to light are injected into the charge transport layer, transported through the charge transport layer to the surface, and by neutralizing the surface charges, an electrostatic latent image is formed on the surface of the photoreceptor. be done. Compared to the single-layer type, the function-separated type has a smaller possibility of trapping generated charges, and each layer does not inhibit its own function.
Charge can be efficiently transported to the surface of the photoreceptor (US Pat. No. 2,803,541).

[0007] As the organic charge generation material used in the charge generation layer, compounds that absorb the energy of irradiated light and efficiently generate charges are selectively used.
Azo pigments (JP-A-54-14967), metal-free phthalocyanine pigments (JP-A-60-143346), metal phthalocyanine pigments (JP-A-50-165)
Publication No. 38), squarium salt (Unexamined Japanese Patent Publication No. 53-2)
7033).

As the charge transport material used in the charge transport layer, it is necessary to select a compound that has a high charge injection efficiency from the charge generation layer and also has a high charge mobility within the charge transport layer. For this purpose, compounds with low ionization potential and compounds that easily generate cation radicals are selected, such as triarylamine derivatives (Japanese Patent Laid-Open No. 53
-47260 Publication), hydrazone derivatives (Japanese Patent Publication No. 57-101844), oxadiazole derivatives (Japanese Patent Publication No. 34-5466), pyrazoline derivatives (Japanese Patent Publication No. 52-4188), stilbene derivatives (Japanese Patent Publication No. 52-4188) 1980-198043), triphenylmethane derivatives (Japanese Patent Publication No. 45-555), 1
,3-butadiene derivative (JP-A-62-287257
(No. Publication) etc. have been proposed. However, these charge mobilities are small compared to inorganic materials,
The sensitivity is still unsatisfactory.

[0009] As hydrazone derivatives, various compounds other than those mentioned above have been proposed.
Publication No. 275 has the following general formula

0010

[Chemical formula 3]

(In the formula, R1, R2, R3, and R4 represent those described in the above publication.) A hydrazone compound is described. JP-A No. 59-37549 has the following general formula:

0012

[C4]

(In the formula, R1, R2, R3, R4,
Ar1 and Ar2 represent those described in the above publication. )
A hydrazone compound represented by is described. JP-A No. 60-260051 has the following general formula:

[0014]

[C5]

(In the formula, R1, R2, R3, Ar,
Z and n represent those described in the above publication. ) are described. However, these compounds still have insufficient charge mobility and low sensitivity.
It also has the disadvantage of a large residual potential.

[0016] As described above, the reality is that a charge transporting material that is practically satisfactory as an electrophotographic photoreceptor has not yet been found.

[0017]

[Means for Solving the Problems] As a result of intensive research aimed at solving the above problems, the present inventors have completed the present invention.

That is, the present invention provides general formula (I)

[0019]

[C6]

(In the formula, R1 represents a hydrogen atom, an optionally substituted alkyl group, an aryl group, or an aralkyl group, and R2 represents a hydrogen atom, a hydroxyl group, an optionally substituted alkyl group, an alkoxy group, or an aryl group. , represents an aralkyl group, dialkylamino group, or diarylamino group.R
3. R4 are the same or different and represent a hydrogen atom, an optionally substituted alkyl group, an aryl group, or an aralkyl group. R5 and R6 represent an alkyl group, an aryl group, an aralkyl group, or a heterocyclic group which may be substituted the same or differently, or a residue in which R5 and R6 form a ring together with the adjacent nitrogen atom. . Ar represents an arylene group or a heterocyclic group. ), and further includes an electrophotographic photoreceptor comprising a conductive support and a photosensitive layer formed thereon as essential components, the carbazole compound represented by the general formula (I) above. The present invention provides an electrophotographic photoreceptor characterized by containing a carbazole compound in a photosensitive layer.

Regarding the general formula (I), the optionally substituted alkyl group represented by R1 includes those having usually 1 to 4 carbon atoms, such as a methyl group, an ethyl group, and an n-butyl group. When substituted, the substituent is usually an alkoxy group or the like. The optionally substituted aryl group usually includes a phenyl group, a naphthyl group, etc.
When substituted, the substituent is usually an alkyl group, an alkoxy group, etc. Examples of the aralkyl group which may be substituted usually include a benzyl group, and substituents when substituted are usually an alkyl group, an alkoxy group, etc. R1 may be a hydrogen atom or any of these, but is not particularly limited, but is preferably an optionally substituted alkyl group or an optionally substituted aryl group for ease of production.

Regarding the general formula (I), the optionally substituted alkyl group represented by R2 includes those having usually 1 to 4 carbon atoms, such as a methyl group, an ethyl group, and an n-butyl group. The substituents in the case of substitution are the same as those described above. Examples of the alkoxy group which may be substituted usually include a methoxy group and an ethoxy group, and when substituted, the substituent is usually an aryl group and the like. The aryl group which may be substituted usually includes a phenyl group, a naphthyl group, etc., and the substituents when substituted are the same as those mentioned above. Examples of the optionally substituted aralkyl group include a benzyl group and the like, and when substituted, the substituents are the same as above. Examples of the optionally substituted dialkylamino group usually include a dimethylamino group and diethylamino group, and when substituted, the substituent is usually an aryl group and the like. The optionally substituted diarylamino group usually includes a diphenylamino group, and when substituted, the substituent is usually an alkyl group, an alkoxy group, etc. R2 may be a hydrogen atom, a hydroxyl group, or any of these and is not particularly limited, but is preferably a hydrogen atom, an optionally substituted alkyl group, or an optionally substituted alkoxy group from the viewpoint of easy production. .

[0023] Regarding the general formula (I), the optionally substituted alkyl group represented by R3 and R4 includes those having usually 1 to 4 carbon atoms, such as methyl group, ethyl group, n-butyl group, etc. When substituted, the substituents are the same as above. The aryl group which may be substituted usually includes a phenyl group, a naphthyl group, etc., and the substituents when substituted are the same as those mentioned above. Examples of the optionally substituted aralkyl group include a benzyl group and the like, and when substituted, the substituents are the same as above. R3 and R4 may be the same or different and may be a hydrogen atom or any of these and are not particularly limited, but from the viewpoint of easy production, a hydrogen atom or an optionally substituted alkyl group is preferred.

Regarding the general formula (I), the optionally substituted alkyl group represented by R5 and R6 includes those having usually 1 to 4 carbon atoms, such as methyl group, ethyl group, n-butyl group, etc. When substituted, the substituents are the same as above. The aryl group which may be substituted usually includes a phenyl group, a naphthyl group, etc., and the substituents when substituted are the same as those mentioned above. Examples of the optionally substituted aralkyl group include a benzyl group and the like, and when substituted, the substituents are the same as above. The optionally substituted heterocyclic group usually includes a pyridyl group, and the substituent when substituted is usually an alkyl group, an alkoxy group, etc. R5, R
6 may be the same or different, and may be any of these, and
Although R5 and R6 may form a ring together with adjacent nitrogen atoms, an optionally substituted alkyl group and an optionally substituted aryl group are preferred from the viewpoint of easy production.

The carbazole compound represented by the general formula (I) of the present invention can be easily synthesized by any known method. For example, general formula (II)

[0026]

[C7]

(wherein R3, R4, Ar are the formula (
Same as I). X represents a halogen atom. ) was used as a Grignard reagent, and then dimethylformamide was added to produce the corresponding aldehyde compound (J. Org. Chem., 26,
2225, 1961), which is converted into general formula (III)

[0028]

[Chemical formula 8]

A hydrazone compound is produced by reacting with a hydrazine compound represented by the formula (wherein R5 and R6 are the same as in formula (I)). This hydrazone compound and the general formula (I
V)

[0030]

[Chemical formula 9]

A carbazole compound represented by the formula (wherein R1 and R2 are the same as in formula (I) and X represents a halogen atom) is mixed in the presence of a Group VIII transition metal compound, a triarylphosphine, and a basic compound. (Japanese Unexamined Patent Publication No. 58-65275, J.O.
rg. Chem. , 37, 2320, (197
2)) The carbazole compound of the present invention can be obtained. Examples of the Group VIII transition metal compound used at this time include cobalt metal, nickel metal, palladium metal, and rhodium metal. Triarylphosphines used include triphenylphosphine, tri-O-tolylphosphine, tris(2-methyl-5-t-butylphenylphosphine), tris(2
, 5-diisopropylphenyl)phosphine, and the like. Basic compounds used include potassium hydroxide, sodium hydroxide, sodium hydrogen carbonate,
Examples include potassium carbonate and amines. The reaction can be carried out without a solvent or in a solvent such as dimethylformamide, dimethylsulfoxide, N-methylpyrrolidone, dioxane, toluene, xylene, or the like. The reaction temperature is carried out in the range of room temperature to 200 °C, usually 0.5 to 200 °C.
It will be completed in 30 hours.

The carbazole compounds represented by the general formula (I) will be specifically illustrated below (compounds (1) to (76)), but the present invention is not limited thereto.

[0033]

[Chemical formula 10]

[0034]

[Chemical formula 11]

[0035]

[Chemical formula 12]

[0036]

[Chemical formula 13]

[0037]

[Chemical formula 14]

[0038]

[Chemical formula 15]

[0039]

[Chemical formula 16]

[0040]

[Chemical formula 17]

[0041]

[Chemical formula 18]

[0042]

[Chemical formula 19]

[0043]

[C20]

[0044]

[C21]

[0045]

[C22]

[0046]

[C23]

[0047]

[C24]

These carbazole compounds can be used alone or in combination of two or more.

These compounds are soluble in many solvents, such as aromatic solvents such as benzene, toluene, xylene, tetralin, and chlorobenzene; halogen solvents such as dichloromethane, chloroform, trichloroethylene, tetrachloroethylene, and carbon tetrachloride; Solvent; methyl acetate,
Ester solvents such as ethyl acetate, propyl acetate, methyl formate, and ethyl formate; Ketone solvents such as acetone and methyl ethyl ketone; Ether solvents such as diethyl ether, dipropyl ether, dioxane, and tetrahydrofuran; methanol, ethanol, isopropyl alcohol, etc. Soluble in alcoholic solvents; dimethylformamide, dimethylacetamide, dimethylsulfoxide, etc.

[0050] In producing the electrophotographic photoreceptor,
For example, a charge generation layer and a charge transport layer are formed in the form of a thin film on a conductive support. As the base material of the conductive support, metals such as aluminum and nickel, metal-deposited polymer films, metal-laminated polymer films, etc. can be used, and the conductive support is formed in the form of a drum, sheet, or belt. form the body.

The charge generation layer is made of a charge generation material and, if necessary, a binder and additives, and can be produced by a vapor deposition method, a plasma CVD method, a coating method, or the like.

The charge generating material is not particularly limited, and any organic or inorganic material may be suitably used as long as it absorbs irradiated light of a specific wavelength and can efficiently generate charges. Can be done. Examples of organic charge generating materials include perylene pigments, polycyclic quinone pigments, metal-free phthalocyanine pigments, metal phthalocyanine pigments, bisazo pigments, trisazo pigments, thiapyrylium salts, squarium salts, and azulenium pigments. A charge generation layer can be formed by dispersing it in a binder and coating it. Among them, the X-type metal-free phthalocyanine pigment is the most excellent in the semiconductor laser wavelength region, and the dibromoanthanthrone pigment is the most excellent in the visible light region in terms of sensitivity. Examples of the inorganic charge generating material include selenium, selenium alloy, cadmium sulfide, zinc oxide, amorphous silicon, amorphous silicon carbide, and the like.

The thickness of the formed charge generation layer is 0.1
Preferably 2.0 μm to 2.0 μm, more preferably 0.1 μm
The thickness is between 1.0 μm and 1.0 μm.

Next, a charge transport layer containing a carbazole compound represented by formula (I) is formed in the form of a thin film on the charge generation layer. A coating method is mainly used to form a thin film, in which a carbazole compound represented by the general formula (I) is dissolved in a solvent together with a binder if necessary, coated on the charge generation layer, and then dried. Bye.

[0055] The solvent used is one in which the above carbazole compound and the binder used as necessary are dissolved;
Moreover, there is no particular limitation as long as the solvent does not dissolve the charge generation layer.

The binder used as necessary is not particularly limited as long as it is an insulating resin, and examples thereof include condensation polymers such as polycarbonate, polyarylate, polyester, and polyamide; polyethylene, polystyrene, and styrene-acrylic copolymer. Addition polymers such as polymers, polyacrylate, polymethacrylate, polyvinyl butyral, polyacrylonitrile, polyacrylamide, acrylonitrile-butadiene copolymer, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer; polysulfone, polyethersulfone, silicone Resins and the like can be used as appropriate, and one type or a mixture of two or more types can be used.

The amount of the binder used is 0.1 to 3, preferably 0.1 to 2, by weight relative to the carbazole compound represented by formula (I). If the amount of binder is greater than this, the concentration of the charge transport material in the charge transport layer will be low, resulting in poor sensitivity.

In addition, in the present invention, the above-mentioned triarylamine derivatives, hydrazone derivatives other than the compounds of the present invention, oxadiazole derivatives, pyrazoline derivatives, stilbene derivatives, triphenylmethane derivatives, 1,3 It is also possible to use a combination of known charge transport materials such as -butadiene derivatives.

[0059] The coating means for the charge transport layer is not limited, and for example, a dip coater, a bar coater, a calendar coater, a gravure coater, a spin coater, etc. can be used as appropriate, and electrodeposition coating can also be used. is also possible.

The thickness of the charge transport layer thus formed is preferably 10 to 50 μm, more preferably 10 to 30 μm. If the film thickness is greater than 50 μm, it will take more time to transport the charges, and the probability that the charges will be captured will also increase, causing a decrease in sensitivity. On the other hand, if it is smaller than 10 μm, the mechanical strength will decrease and the life of the photoreceptor will be shortened, which is not preferable. As described above, an electrophotographic photoreceptor containing a carbazole compound represented by the general formula (I) in the charge transport layer can be produced. Depending on the requirements, an undercoat layer, adhesive layer, barrier layer, etc. may be provided, and these layers may be made of, for example, polyvinyl butyral, phenol resin, polyamide, or the like. Furthermore, a surface protective layer can also be provided on the surface of the photoreceptor.

When using the electrophotographic photoreceptor thus obtained, first the surface of the photoreceptor is negatively charged using a corona charger or the like. After being charged, charges are generated in the charge generation layer by exposure to light, and positive charges are injected into the charge transport layer, which are transported through the charge transport layer to the surface, neutralizing the negative charges on the surface. be done. On the other hand, negative charges will remain in the unexposed areas. In the case of regular development, a positive toner is used, and the toner adheres to the portion where this negative charge remains and is developed. In the case of reversal development, negative toner is used, and the toner adheres to the areas where the electric charge has been neutralized.
It will be developed. The electrophotographic photoreceptor of the present invention can be used in any developing method and can provide high image quality.

In the present invention, an electrophotographic photoreceptor can also be produced by first providing a charge transport layer on a conductive support and then providing a charge generation layer thereon. In this case,
First, the surface of the photoreceptor is positively charged, and after exposure, the generated negative charges neutralize the surface charges of the photoreceptor, and the positive charges are transported to the conductive support through the charge transport layer.

Further, in the present invention, a single layer type photoreceptor including a charge generating material and a charge transporting material in the same layer can be used.
In that case, the charge generating material and the charge transporting material may be dissolved together with the binder, dispersed and coated on the support to a thickness of 10 to 30 .mu.m.

[0064]

EXAMPLES The present invention will be specifically explained below with reference to Synthesis Examples and Examples, but the present invention is not limited thereto.

Synthesis Example 1 Synthesis of compound (6) (a)
Synthesis of 4-formylstyrene In a 1 liter four-necked flask equipped with a stirring device, cooling tube, nitrogen inlet tube, dropping funnel, and thermometer, 14.6 g (0.6 mol) of metallic magnesium, 100 ml of dry tetrahydrofuran, and a small amount of Added iodine. After activating metallic magnesium by heating to 60° C. with stirring, 83.1 g (0.6 mol) of 4-chlorostyrene dissolved in 100 ml of dry tetrahydrofuran was added dropwise. After the dropwise addition was completed, the mixture was reacted for 1 hour while being maintained at 60°C. Next, the reaction solution was cooled to 20° C., and 43.8 g (0.6 mol) of dry dimethylformamide dissolved in 100 ml of dry tetrahydrofuran was added dropwise. After the dropwise addition was completed, the mixture was reacted for 1 hour while being maintained at 20°C.

200 ml of dilute hydrochloric acid and 300 ml of ether were added to the reaction solution and mixed well, and the ether layer was separated. This ether solution was washed with water three times, dried over anhydrous sodium sulfate, and then the ether was distilled off. The obtained colorless liquid was distilled under reduced pressure to obtain 70.5 g of 4-formyl-styrene.
(yield 89%) was obtained.

(b) Synthesis of 4-formylstyrene-N-methyl-N-phenylhydrazone 300 m equipped with a stirrer, a cooling tube, a dropping funnel, and a thermometer.
l In a 4-neck flask, 24.4 g (0.2 mol) of 1-methyl-1-phenylhydrazine, 100 ethanol
ml and 2 g of acetic acid were added. 4-formylstyrene dissolved in 50 ml of ethanol with stirring at room temperature26.
4 g (0.2 mol) was added dropwise. After the dropwise addition was completed, the reaction was allowed to proceed for 6 hours.

The precipitated yellow solid was filtered, washed once with ethanol, and then recrystallized from ethanol/ethyl acetate to yield 43.9 g (93%) of 4-formylstyrene-N-methyl-N-phenylhydrazone. Obtained.

(c) Synthesis stirring device for compound (6);
3 equipped with cooling pipe, nitrogen introduction pipe, dropping funnel, and thermometer
00ml 4-necked flask, 4-obtained in (b)
Formylstyrene-N-methyl-N-phenylhydrazone 4.72g (0.02mol), 3-bromo-9-methylcarbazole 5.20g (0.02mol), tri-o-tolylphosphine 0.12g, palladium acetate 0
．． 045 g of tributylamine, 3.71 g of tributylamine, and 20 g of dimethylformamide were added thereto, nitrogen gas was blown into the mixture, the mixture was heated to 100° C. with stirring, and reacted for 5 hours.

The reaction solution was cooled to room temperature, and 50% of ethyl acetate was added.
ml was added. Thereafter, 50 ml of water was added and mixed well, and the ethyl acetate layer was separated. This ethyl acetate solution was washed with water three times, dried over anhydrous sodium sulfate, and then ethyl acetate was distilled off. The obtained yellow solid was recrystallized from hexane/ethyl acetate to obtain 7.06 g of compound (6) (yield 85%,
mp. 200-201°C).

Synthesis Example 2 Synthesis of compound (17) (a)
Synthesis of 4-formylstyrene-N,N-diphenylhydrazone 30 units equipped with a stirring device, a cooling tube, a dropping funnel, and a thermometer.
In a 0ml four-necked flask, add 44.1g (0.2mol) of 1,1-diphenylhydrazine hydrochloric acid and 1 mol of ethanol.
00ml and 2g of acetic acid were added. 4-formylstyrene 2 dissolved in 50 ml of ethanol with stirring at room temperature
6.4 g (0.2 mol) was added dropwise. After dripping, 5
Allowed time to react.

The precipitated yellow solid was filtered, washed once with ethanol, and then recrystallized from ethanol/ethyl acetate to obtain 52.4 g (88%) of 4-formylstyrene-N,N-diphenylhydrazone. .

(b) Synthesis stirring device for compound (17),
3 equipped with cooling pipe, nitrogen introduction pipe, dropping funnel, and thermometer
00ml 4-necked flask, 4-obtained in (a)
Formylstyrene-N,N-diphenylhydrazone 5
．． 96g (0.02mol), 3-bromo-9-ethylcarbazole 5.48g (0.02mol), tri-o-tolylphosphine 0.12g, palladium acetate 0
．． 045 g, tributylamine 3.71 g, and N-methylpyrrolidone 20 g were added, nitrogen gas was blown into the mixture, and the mixture was heated to 120° C. with stirring and reacted for 3 hours.

The reaction solution was cooled to room temperature, and 50% of ethyl acetate was added.
ml was added. Thereafter, 50 ml of water was added and mixed well, and the ethyl acetate layer was separated. This solution was washed with water three times, dried over anhydrous sodium sulfate, and then ethyl acetate was distilled off. The obtained yellow solid was recrystallized from hexane/toluene,
Compound (17) 9.23 g (yield 94%, mp.
228-230°C) was obtained. The obtained compound (17
) NMR spectrum (CDCl3) is shown in Figure 1.

Example 1 As a charge generating material, 5 g of X-type metal-free phthalocyanine and 5 g of butyral resin (S-LEC BM-2, manufactured by Sekisui Chemical Co., Ltd.) were dissolved in 90 ml of cyclohexanone and kneaded in a ball mill for 24 hours. The resulting dispersion was coated onto an aluminum plate using a bar coater to a dry film thickness of 0.2 μm and dried to form a charge generation layer.

Next, as a charge transport material, 5 g of the compound (6) obtained in Synthesis Example 1 and 5 g of polycarbonate resin (Lexan 141-111, manufactured by Engineering Plastics Co., Ltd.) were dissolved in 90 ml of dioxane. A charge transport layer was formed by coating the resulting charge generation layer with a blade coater to a dry film thickness of 25 μm and drying.

The electrophotographic photoreceptor thus produced was tested using an electrostatic copying paper tester EPA-manufactured by Kawaguchi Electric Seisakusho Co., Ltd.
8100 and charged with a corona voltage of -6.0 kV, the initial surface potential V0 was -770V. The surface potential V5 after being left in the dark for 5 seconds was -715V. Next, 790 nm monochromatic light was irradiated, and the half-life exposure amount E1/2 was determined to be 0.33 μJ/cm2.
The residual potential VR was -6V.

Next, after repeating 10,000 times, V0, V5,
When E1/2 and VR were measured, they were -765 each.
V, -710V, 0.33μJ/cm2, -9V
Therefore, the performance of the photoreceptor had hardly deteriorated.

Examples 2 to 10 Electrophotographic photoreceptors were produced in the same manner as in Example 1, except that the compounds shown in Table 1 were used as charge transport materials, and their performance was evaluated. The results are shown in Table 1.

[0080]

[Table 1]

Example 11 An electrophotographic photoreceptor was produced in the same manner as in Example 1, except that titanyl phthalocyanine was used as the charge generating material instead of the X-type metal-free phthalocyanine, and its performance was evaluated. As a result, V0, V5, E1/2, and VR are -805V, -760V, and 0.32μJ/cm2, respectively.
, -5V. Next, after repeating 10,000 times, V0
, V5, E1/2, and VR were measured, and they were -805V, -755V, and 0.33μJ/cm2, respectively.
, -6V, and the performance of the photoreceptor was hardly deteriorated.

Example 12 As a charge generating material, titanyl phthalocyanine was used instead of the X-type metal-free phthalocyanine, and as a charge transporting material,
The compound obtained in Synthesis Example 2 (instead of compound (6))
An electrophotographic photoreceptor was manufactured in the same manner as in Example 1 except that 17) was used, and performance evaluation was performed. As a result, V0,
V5, E1/2, VR are -835V, - respectively
It was 740V, 0.32μJ/cm2, -9V. Next, after repeating 10,000 times, V0, V5, E
When 1/2 and VR were measured, they were -835V and 1/2, respectively.
-740V, 0.33μJ/cm2, -13V, and the performance of the photoreceptor had hardly deteriorated.

As described above, it was found that the electrophotographic photoreceptor according to the present invention has excellent sensitivity and durability both for the first time and after 10,000 times.

Comparative Example 1 An electrophotographic photoreceptor was prepared in the same manner as in Example 1, except that the following compound (A) was used instead of compound (6) as a charge transport material, and its performance was evaluated. The result is V0
, V5, E1/2, VR are each -710V,
-605V, 0.71μJ/cm2, -35V
Met. Next, after repeating 10,000 times, V0, V5,
When E1/2 and VR were measured, they were -680V each.
, -595V, 0.98μJ/cm2, -80V
The results were poor in both chargeability and sensitivity.

[0085]

[C25]

Comparative Example 2 An electrophotographic photoreceptor was prepared in the same manner as in Example 1, except that the following compound (B) was used instead of compound (6) as a charge transport material, and its performance was evaluated. The result is V0
, V5, E1/2, VR are each -765V,
-610V, 0.68μJ/cm2, -57V
Met. Next, after repeating 10,000 times, V0, V5,
When E1/2 and VR were measured, they were -660V each.
, -510V, 1.05μJ/cm2, -95V
The results were poor in both chargeability and sensitivity.

[0087]

[C26]

[0088]

[Effect of the invention] The carbazole compound in the present invention is
An electrophotographic photoreceptor characterized by containing the charge transport material in the photosensitive layer has a stable initial potential, small dark decay, and excellent sensitivity. In addition, it shows little deterioration due to repeated use, has excellent durability, and can be used satisfactorily as an electrophotographic photoreceptor.

[Brief explanation of drawings]

FIG. 1 is an NMR spectrum (CDCl3) of compound (17) obtained in Synthesis Example 2.

Claims (2)

[Claims] Claim 1: General formula (I) [Formula 1] (wherein, R1 represents a hydrogen atom, an optionally substituted alkyl group, an aryl group, or an aralkyl group, and R2 represents a hydrogen atom, a hydroxyl group, or an optionally substituted alkyl group; R3 and R4 are the same or different and each represents a hydrogen atom, an optionally substituted alkyl group, an aryl group, or Represents an aralkyl group.R5,
R6 represents an alkyl group, an aryl group, an aralkyl group, or a heterocyclic group which may be the same or different substituted, or a residue in which R5 and R6 form a ring together with the adjacent nitrogen atom. Ar represents an arylene group or a heterocyclic group. ) Carbazole compound shown by. [Claim 2] An electrophotographic photoreceptor comprising a conductive support and a photosensitive layer formed thereon as essential components, comprising general formula (I) [Chemical formula 2] (wherein R1, R2, R3 , R4, R5, R6, A
r is the same as above. ) An electrophotographic photoreceptor comprising a carbazole compound represented by the following formula as a charge transporting material in a photosensitive layer.